1. Field of the Invention
The present invention relates to a typesetting fixing method, a display plate and a timepiece.
2. Description of the Related Art
On a dial plate for a timepiece, there are numbers or characters representing time and the like, indicators (so-called hour characters) to replace them, various scale marks, symbols, or the like, to be disposed.
These hour characters and the like may be two-dimensionally formed by printing. However, in order to make a high-quality finish, it is preferable to three-dimensionally express them. A “typesetting” method of forming a typesetting member as a separate member and disposing and fixing the typesetting member on a dial plate is widely used.
In the related art, it is general to make a typesetting member of a metal material, and in order to fix a typesetting member, mechanical swaging or bonding is often used.
That is, for example, a typesetting member is fixed by providing a leg on the rear side of the typesetting member, and forming a hole for inserting the leg in a dial plate made of a metal material or a resin material, and disposing the typesetting member on the dial plate, and then fixing the leg on the rear side of the dial plate by mechanical swaging, bonding using an adhesive, or the like.
In this regard, according to recent evolution of a molding technology, it has become possible to make typesetting members which are fine components of resin materials.
In a case of making both of a dial plate and a typesetting member of resin materials, it is possible to fix the typesetting member on the dial plate by various methods of joining resins.
Examples of the methods of joining resins include fixing using an adhesive, thermo compression bonding, and ultrasonic joining.
However, it takes a lot of trouble to fix a fine component by an adhesive, and due to some reason such as extrusion of the adhesive, it may be impossible to make a beautiful finish.
In JP-A-2001-198982, there has been disclosed a method of welding resins by a laser welding technique.
However, a typesetting member is a fine component to be disposed on a dial plate, and on the dial plate of a timepiece, slight flaws such as deformation and burns due to heat and dirt are easy to notice. Therefore, product quality decreases.
In this regard, the method of the related art as described above has an issue that, since fine heat control is impossible, it is difficult to perform stable welding in a fine area of a fine component. And, it is especially difficult to perform welding of a component strongly required to eliminate influence of heat on the external appearance, like a typesetting member of a timepiece.